We have a new addition in our family! Ten days ago, our family welcomed baby Lucas, brother to two adoring sisters. Our family had been hoping for a boy during my cousin’s entire pregnancy, so when he entered this world and emerged with his little [man parts], we were all ecstatic! (:
With baby Lucas in our family, I wanted to share with you all some of the research that was presented during the conference I attended a few weeks ago. The lecture was given by Dr. Laurel Trainor, a psychology professor from McMaster University. She runs her research in the University’s Auditory Development Lab, where she studies the perception of sound in infants, children, and adults, as well as the acquisition of music and language. Her research focuses on what infants perceive when they listen to speech and music, how this changes as they grow, and what influences how sound perception develops.
Why do caregivers talk and sing to infants who don’t understand the words? Can infants recognize tunes? What aspects of the musical structure do they encode? How do infants perceive pitch, pitch patterns, and melodies? How is rhythm perceived? What is the multisensory relation between music and movement? How does musical training affect brain development? These are all questions she aims to answer in the lab.
Before getting into any infant research, though, we must familiarize ourselves with how we perceive pitch as adults. In our daily lives, sound is always present. Sounds reach our ears as one massive complex sound, and it may become unclear which sources certain sound waves come from. Our brain parses this complex sound to determine one source of sound from another.
But how does our brain do this?
It uses fundamental frequencies and overtones. Our brains understand that integer multiples of a certain fundamental frequency are mostly produced from the same source. Pitch is created in the auditory cortex in the brain, where harmonics are grouped together and perceived as pitch, at the fundamental frequency. Brains are amazing things. But to take it a step further, shall we? If the fundamental frequency was missing, but all the other harmonics are still present, we’ll still perceive the pitch at the fundamental frequency! Craziness. I know.
So this leads to the question: Can babies tell pitch with the missing fundamental?
After conducting an experiment, it was shown that babies at 3 months cannot perceive pitch at the fundamental… But they can at 4 months. This means that virtual pitch perception emerges in babies between the ages of 3 and 4 months!
Another research question that was looked at was whether babies can tell if a pitch has a mistuned harmonic. This means taking one of the harmonics of a fundamental and altering it slightly. To adults, when presented with a pitch containing a mistuned harmonic, we should hear two pitches. The question is: do babies hear two pitches, too? The answer is yes! The ability to detect mistuning emerges between 4 and 6 months! Babies are amazing creatures.
Aside from research in pitch discrimination, Dr. Trainor also did work on how babies respond to rhythm. Young infants can discriminate rhythmic patterns with ease. First, we need to break down the concept of rhythm. Beats are derived perceptually from the surface of the music, while meter is the hierarchy of beat levels. As musicians, we are capable of internalizing sound events when no sound is present. In other words, we can hear strong beats even if no sound is there to emphasize the beats. In North America, we are enculturated to Western meters. When we’re presented with complex meters, the music is no longer isochronous (isochronous=equally spaced metrical divisions). When adults are first presented with a simple rhythm, then presented with a similar melody in a complex rhythm, we can generally tell that the two are different. However, when we are presented with a complex rhythm first, and then presented with the simple rhythm afterwards, it becomes more difficult to distinguish the two rhythms. When we are being presented with the simple rhythm first, the complex rhythm immediately sounds odd when we hear it. However, when presented with the complex rhythm first, our enculturated minds are working so hard to fit the rhythm into a simple meter that the simple rhythm that comes afterwards is also jumbled in our minds.
At six months, babies can distinguish between simple and complex rhythms when presented with them in either order. However, by 12 months, babies will have difficulty distinguishing between the rhythms when the complex rhythm comes first, just like most adults in North America, because they have also gotten enculturated to simple meters.
The last concept Dr. Trainor introduced in her lecture was that there is no such thing as “too early” to begin musical training. Studies showed that babies who undergo early childhood classes such as the Suzuki program develop sensitivity to sound 2 to 3 years faster than those who don’t. Her research also shows that music trains executive functions such as memory and behavior control. She showed us a video comparing two children at 12 months, one who took the Suzuki classes, and one who didn’t. The two children were presented with a xylophone and two mallets. The child who took the Suzuki classes attempted (rather successfully, for a one-year-old) to play the instrument, hitting the xylophone, alternating hands. This was already considered advance behavior, as babies at that age would probably only be able to control both hands to do the same thing at the same time, while this child was already showing signs of being able to control each hand independently. The other child, who did not take any classes, didn’t do anything with the instrument itself. He was eating the mallets. (: Cute, I know.
More of Dr. Trainor’s research shows that babies are sensitive to rhythm at 6 months, but they generally cannot follow tempo with whole-body movements until the age of 4. They can, however, relate movement to rhythm. This means that they will move their bodies slower or faster depending on the tempo of the music, but they will not be able to motorically synchronize with a beat.
If any of you are interested to see more of Dr. Trainor’s research, you can visit her research projects page here!
That’s it for today! Until next week,
Dream big, music-makers! (:
thelittlepianist 